Be active. Do small sets of pushups or other exercise throughout the day if you can. Even sets of 10 here and there will help, or jumping jacks. Maintain good posture. Don’t be inactive for too long. Be sure to eat a complete breakfast, as eating signals your metabolism to rise. It may help to eat several smaller meals or snacks throughout the day. I aim for 5–6 “meals.” This means I eat smaller breakfasts but I eat two of them, a small lunch, then a snack, then another small dinner and maybe some fruit later an hour or two before bed.
Also I just read that if you drink water it helps. BUT if you can drink every glass of your 8 glasses of water iced, you will burn 10 more calories a day, and this equals a pound per year, just for putting ice in your water! Hey, you asked for small things! (Also try chugging 16+oz of ice water when you wakeup too, your body needs to boost to maintain temperature and this raises metobalism)